ST. LOUIS, April 21, 2017 . . . This marks an important milestone for The Loop Trolley as crews electrify the wires that will power the trolleys and the wires officially go LIVE. Testing of the traction power substation and overhead wires will occur the week of April 24th. Crews will be visible along the tracks on Tuesday as final preparations are made to power up the system and assess any hazards. The testing will continue through Friday, with all work to take place between 7 a.m. and 6 p.m. Once this testing begins, all wires are considered “hot” and electrified at all times, and the public will need to be mindful of the related safety precautions.